Training Changes Muscle Twitch Direction Induced by TMS
Author Information
Author(s): Giacobbe Viola, Volpe Bruce T, Thickbroom Gary W, Fregni Felipe, Pascual-Leone Alvaro, Krebs Hermano I, Edwards Dylan J
Primary Institution: Burke-Cornell Medical Research Institute, White Plains, NY, USA
Hypothesis
A short period of repetitive gentle wrist movements in a direction opposite to the initial TMS-twitch direction would result in a change of twitch direction elicited by TMS, and a corresponding reduction in descending drive to the antagonist muscle.
Conclusion
Five minutes of repetitive wrist movements can change the direction of a TMS-induced muscle twitch and reduce excitability in the antagonist muscle.
Supporting Evidence
- Repetitive motor training was sufficient for TMS to evoke movements in the practiced direction opposite to the original twitch.
- The direction change of the movement was associated with a significant decrease in MEP amplitude of the antagonist muscle.
- Most subjects retained the effect of the newly-acquired direction for at least 10 minutes before reverting to the original.
Takeaway
If you practice moving your wrist in one direction, it can change how your muscles respond to a brain stimulation that usually makes them twitch in the opposite direction.
Methodology
Twenty right-handed healthy volunteers performed wrist movements in the direction opposite to the initial TMS-induced twitch for 5 minutes, and TMS was applied to measure muscle responses before and after training.
Limitations
The study had a limited sample size and lacked power for multi-factorial analysis.
Participant Demographics
Twenty right-handed healthy volunteers, mean age 28 years, range 22-37 years, with no history of neurological or psychiatric illness.
Statistical Information
P-Value
p<0.01 for initial direction change, p<0.05 for MEP amplitude decrease
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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